A number of techniques are available for treating heart disease and diseases of other organs percutaneously. Examples of such techniques include delivery of genes and therapeutic substances, including the delivery of genes and therapeutic substances for percutaneous myocardial revascularization (PMR). This procedure is performed to increase blood perfusion through the myocardium of a patient. For example, in some patients, the number of lesions in coronary vessels is so great or the location so remote in the patient vasculature that restoring blood flow to the heart muscle is difficult. Percutaneous myocardial revascularization (PMR) has been developed as an alternative to techniques which are directed at bypassing or removing lesions. PMR is performed by boring holes directly into the myocardium of the heart. Positive results have been demonstrated in some human patients receiving PMR treatments. These results are believed to be caused in part by blood flowing from within a heart chamber through patent holes formed by PMR to the myocardial tissue. Suitable PMR holes have been proposed to be burned by laser, cut by mechanical means, and burned by radio frequency devices. Increased blood flow to the myocardium is also believed to be caused in part by the heating response to wound formation, specifically, the formation of new blood vessels in response to the newly created wound.
Several aspects of PMR procedures could be improved upon. One area for improvement is in the preparation of PMR injection catheters for use by the treating physician. In particular, at present, the PMR device maybe flushed with a drug to prime the distal needle by flushing the drug through the needle and into a container. This preparation can be awkward and may leave a container of biologically active material which may require further processing. Another aspect which may be further optimized lies in the attachment of the needle to the distal region of the PMR catheter tube. In particular, forces may act upon the needle during both the advancement and retraction of the needle within the heart wall, urging the needle undesirably both into and out of the tube. Improved methods of securing the needle to the tube would be desirable.
During a PMR treatment, a physician may be attempting to treat a three-dimensional space using a catheter having a distal bend. In particular, the physician may be attempting to treat the heart chamber side, anterior, and posterior wall regions. This may presently be difficult to visualize under fluoroscopy as current marking systems for shafts may make interpretation of the catheter distal region orientation somewhat ambiguous. The heart chamber wall thickness can vary depending on the chamber and wall region being treated. In particular, the left ventricle wall is thinner in the posterior region relative to the anterior region. Improved devices for variable depth, yet controlled penetration of the heart walls, would be advantageous. As multiple sites of the heart chamber wall are penetrated, a system for tracking the treated versus untreated regions would also be desirable.